A known window blind for a sliding roof system arranged on a vehicle, disclosed in U.S. Pat. No. 7,114,767 B2 (hereinafter referred to as Reference 1) includes a flexible material, a pair of guide rails, and a guide element (guide strip).
The flexible material is positioned in wound-up and extended states. The flexible material serving as a shade sheet is moved in an opening direction to be arranged in the wound-up state to thereby uncover a light transmitting member arranged on the vehicle. The flexible material is moved in a closing direction to be arranged in the extended state to thereby shield the light transmitting member.
The pair of guide rails is arranged on the vehicle so that guide portions arranged to extend along a moving direction of the window blind may face each other. Further, each of the guide portions has a bottom wall portion extending in the moving direction of the window blind, an inner wall portion vertically formed from the bottom wall portion, an outer wall portion vertically formed at a further exterior side of the vehicle than the inner wall portion, and an extending portion extending from a lower end of the outer wall portion toward the center of the vehicle. Each edge portion of the window blind and the guide element are accommodated in an interior space (accommodating space) surrounded by the bottom wall portion, the inner wall portion, the outer wall portion, and the extending portion. The inner wall portion includes a leg (preventing portion) extending from a lower end of the inner wall portion toward the exterior side of the vehicle. The leg prevents the guide element from being loosened from the interior space of the guide portion.
The guide element extends along the moving direction of the window blind while being connected to the edge portion of the window blind in a longitudinal direction of the vehicle, thereby guiding the window blind to be movable along the guide portion.
In the conventional window blind described in Reference 1, the guide portion is configured so as to support one end of the guide element and to hold a connecting portion between the edge portion of the window blind and the other end of the guide element. The window blind is slidably moved along the guide portions. Accordingly, for example, when a tensile force is applied to the window blind, a stress due to the tensile force may concentrate on a slide portion between the window blind and the guide portions. Consequently, a sliding resistance may increase when the window blind is moved along the guide portions or the edge portions of the window blind may be worn. Additionally, an operational reliability of the window blind may deteriorate.
A need thus exists for a roller shade apparatus, which is not susceptible to the drawback mentioned above.